You can't opt out completely. When you opt out the ads are still displayed but they are no longer based on your browsing history.. The only way to stop the ads from being displayed is to use an adblocker.
Unfortunately I can't use an adblocker on my old iPad 1 and when I opted out I kept getting R rated lingerie ads.
๐ฎ Once I opted back in they soon changed to more relevant ads.
http://pages.ebay.com.au/help/account/adchoice.html#will
